condition mean min max ZT0-3 2.847945 2.847945 2.847945 ZT4-7 2.288485 2.288485 2.288485 ZT8-11 2.2113050000000003 2.2113050000000003 2.2113050000000003 ZT12-15 2.35922 2.35922 2.35922 ZT16-19 3.1709899999999998 3.1709899999999998 3.1709899999999998 ZT20-23 2.706785 2.706785 2.706785